src/src/setenv.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Michael Haardt 2015
   6  * Copyright (c) Jeremy Harris 2015 - 2016
   7  * Copyright (c) The Exim Maintainers 2016 */
   8 /* See the file NOTICE for conditions of use and distribution. */
   9
  10 /* This module provides (un)setenv routines for those environments
  11 lacking them in libraries. It is #include'd by OS/os.c-foo files. */
  12
  13
  14 int
  15 setenv(const char * name, const char * val, int overwrite)
  16 {
  17 uschar * s;
  18 if (Ustrchr(name, '=')) return -1;
  19 if (overwrite || !getenv(name))
  20   putenv(CS string_copy_malloc(string_sprintf("%s=%s", name, val)));
  21 return 0;
  22 }
  23
  24 int
  25 unsetenv(const char *name)
  26 {
  27 size_t len;
  28 const char * end;
  29 char ** e;
  30 extern char ** environ;
  31
  32 if (!name)
  33   {
  34   errno = EINVAL;
  35   return -1;
  36   }
  37
  38 if (!environ)
  39   return 0;
  40
  41 for (end = name; *end != '=' && *end; ) end++;
  42 len = end - name;
  43
  44 /* Find name in environment and move remaining variables down.
  45 Do not early-out in case there are duplicate names. */
  46
  47 for (e = environ; *e; e++)
  48   if (strncmp(*e, name, len) == 0 && (*e)[len] == '=')
  49     {
  50     char ** sp = e;
  51     do *sp = sp[1]; while (*++sp);
  52     }
  53
  54 return 0;
  55 }
  56
  57 /* vi: aw ai sw=2
  58 */
  59 /* End of setenv.c */